Electrical connectors comprising insulating body having electrical contacts carried thereby are well own in the art. In the so-called male pin connectors, the insulating body carries pin-like contacts which extend above and below the insulating body to facilitate electrical connection from one element, such as a printed circuit board (PCB), to another element, which may, for example, comprise a so-called female connector. As is well known, a female connector comprises an insulating body which carries an electrical contact which is generally capable of receiving at one end thereof a male pin, and at the other end thereof an electrical conductor which may be another male pin, a single electrical conductor, or a single strand of a multiconductor flat ribbon cable. Typically, the aforedescribed male connector and female connector are utilized in a tandem or coupled fashion to provide electrical connection from one element such as the printed circuit paths on a PCB to individual conductors or the multiple conductors of a multiconductor ribbon cable.
The aforedescribed male and female type connectors are generally manufactured with a predetermined number of contacts carried thereby. For example, a typical male connector of the type described above might comprise a length of insulating material having two, ten, twenty, thirty, or any number of pins carried thereby. Similarly, a female connector may comprise a body of insulating material having individual cavities disposed therein, each cavity of which carries an electrical contact. Like the male connectors, the female connectors are commonly manufactured with two, ten, twenty, thirty, etc., contacts.
There are drawbacks associated with the manufacture and use of both male and female connectors of the type described above. The end user may use several connectors, each having a different number of electrical contacts or "positions". He must therefore purchase and inventory many different connector sizes, i.e. he must maintain a supply of 8-position, 12-position, 20-position connectors, etc.
A continuous connector strip for solving this problem was disclosed in U.S. Pat. No. 4,230,387. U.S. Pat. No. 4,832,622 (the '622 patent), whose contents are herein incorporated by reference, describes a better solution to the problem involving continuous extrusion or semi-continuous injection molding. Problems with the continuous extrusion scheme are that only simple header configurations are possible, and the extruded strip must in a subsequent step have holes punched and notches formed. While the semi-continuous injection molding scheme avoids the foregoing problems, it also has drawbacks, which will be best understood from the following description.
The latter method involves use of an angled protuberance (108) (see FIG. 11A of the '622 patent) on the end of a longitudinal spine (106) extending along the strip edge and which serves as the connection device for a number of units (102) which are each composed of a discretely molded segment. After the injection molding and cooling process, each discretely molded segment is removed from the mold cavity and indexed into a position such that the next discretely molded segment will in turn encapsulate, fuse or overmold the protuberance (108) of the previous segment. In this method, the protuberance (108) of the previous segment becomes encapsulated in or fused into the spine (106) and leading end unit (102) of the segment currently being molded. This achieves the interlocking of the two discretely molded segments to form a continuous length.
A first drawback with this method is that, the act of removing the discretely molded segment from the mold and indexing into a position such that the next cycle of the injection mold will encapsulate or fuse the protuberance in exactly the correct position is something that must be done with the highest precision, or the two strips will be out of pitch. Pitch is defined as the distance from one electrical connection device (pin, socket, etc.) to the adjacent one, and is of critical importance to the end assembler of the devices, who has to assemble, for example, a female connector with socket connectors of a given pitch to a male connector with pin connections of the same pitch. This method of interlocking the two discretely molded segments relies entirely on the repositioning of the first segment in precisely the correct location with relation to the mold cavity that will in turn mold the next segment. This is not easy to accomplish in the method described in the '622 patent.
A second drawback of the method presented above is the possibility of having weak joints due to poor materials, poor design, or improper processing conditions during the injection molding process. Weak joints would be subject to breakage, causing the two discretely molded segments to separate during the interconnecting device insertion process, shipment or during the end user's assembly process.